Apparatus for investigating surface profiles



Dec. 1, 1959 H. LAAKSO- APPARATUS FOR INVESTIGATING SURFACE PROFILES Filed March 25, 1957 2 Sheets-Sheet 1 6 7 9 IE1 IE1- .-z

l6" l5 l7 /6) I7 I INVENTOR S Zea/250a Z350 Wm GE QW ATTORNEY Dec. 1, 1959 1.. H. LAAKSO 2,914,938

APPARATUS FOR INVESTIGATING SURFACE PRQF'ILES Filed March 25, 1957 2 Sheets-Sheet 2 INVENTOR Zea/5,1 a a 190 BY GEQCNM ATTORNEY States Patent APPARATUS FOR INVESTIGATING SURFACE PROFILES Leo Laakso, Ypsilanti, Mich., assignor to Marion E. Abbott, trustee, Ann Arbor, Mich.

Application March 25, 1957, Serial No. 648,041

7 Claims. (Cl. 73-105) The present invention relates broadly to measuring and recording equipment, and in its specific phases to a profile inspecting device which utilizes the movements of a workengaging tracer to actuate some adequate indicating meansto disclose'inaccuracies in the profile being tested.

Generally speaking the present invention relates to an inspecting device and is an improvement on instruments of the general type disclosed in US. Patent No. 2,633,020, issued March 31, 1953, to Ernest J. Abbott. In the structure set forth in that patent, a slide assembly carries the tracer unit and a skid-including assembly, the skid of the latter assembly being cooperable with a pilot plane known as an optical flat. This slide assembly is mounted in guideways on a support, with the skid-including assembly being hingedly mounted on such slide assembly, since it has been found that if inaccuracies originally exist or later develop in these guideways suflicient to cause deviation of said slide assembly from its intended plane of movement, such deviations would result in erroneous tracer movements with consequent false indication of profile inaccuracies, and accordingly hinging the skid-including assembly with its associated parts provided a Way to minimize such inaccuracies. The present invention is aimed at a still different structure to overcome this difiiculty, and came out of a recognition of the problem involved and the need of a more positive and simple solution of same.

Accordingly among the objects of the present invention and the carrying out the above stated end, this invention has been aimed to provide a tracer unit carrier with such tracer unit guided in a fixed path by the pilot plane; to provide an actuator for moving said tracer unit carrier; and to so connect said tracer unit carrier to said actuator that any deviations of said actuator from its intended plane of operation cannot be transmitted to said tracer unit carrier.

- Another object has been to provide the tracer unit carrier with a plurality of skids (preferably three) contacting with the pilot plane or optical fiat, and so located as to preclude any possible tilting of said carrier with respect to said plane during operation of the device.

Yet another object has been to provide the actuator with an opening somewhat loosely receiving the tracer unit carrier toestablish an operative connection between said actuator and carrier for endwise movement of same in unison, and to prevent transmission of any deviations in the actuator "movements-to --thecarrier.

Still another object has been to provide spring means acting on the tracer unit carrier and reacting on the actuator for holding the carrier in contact with the pilot plane so as to be movable in a predetermined path controlled by said pilot plane.

Yet another object has been to provide a relatively simple and inexpensive construction for facilitating manufacture while permitting profitable production at a reasonable price.

"ice

, Still further objects and advantages will appear as the.

description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims, the annexed drawings and the following description setting forth in detail certain means for carrying out the invention, such disclosed means illustrating, however, but one of various ways in which the principle of Figure 3 is a top view of the actuator which is used to move the tracer unit carrier.

Figure 4 is a top view of the tracer unit carrier. A work table 5, Figures 1 and 2, is shown from which a standard 6 rises rigidly. A plate 7 is mounted for vertical sliding adjustment on the standard 6, as indicated by the double-ended arrow 8 of Figure 2. A second plate 9 is mounted on the plate 7 for pivotal adjustment in' conventional manner, as indicated by the double-ended arcuate arrow 10 of Figure 1. The standard 6, plate 7, and plate 9 correspond respectively to the elements 2,

9 and 12 of Patent No. 2,633,020, and as no novelty is claimed for the association of these elements nor for the plate adjusting means, the present application will not be encumbered with specific illustration and description of these items.

The plate 9 is provided with a lateral bracket portion 11, Figures 1 and 2, in which a pilot block 12 is fixedly mounted, and the lower side of this block constitutes a strictly accurate pilot plane 13. The block 12 is commonly known as an optical flat.

In the present disclosure, the pilot block 12 rests on any suitable supporting means 14, which is preferably yieldable, and is held solidly down by adjusting screws 15. These screws 15 are threaded through a plate 16 which overlies the pilot block 12, and said plate 16 is conventionally secured in place such as by screws 17 upon shoulders 18 in the bracket portion 11 of the plate 9 Under the pilot block 12, the bracket portion 11 is formed with guideways 19, and an actuator slide 20 is slidably engaged with said guideways 19 for proceeding and receding movements in a plane substantially parallel with the pilot plane 13. Such movements may be im-' parted to the actuator slide 20 by conventional means.

For illustrative purposes, a nut 21, Figures 1 and 3, is

shown on'the slide 20 and engaging a reversible rotationscrew 22. This screw may be driven in any conventional manner, such for instance as is the screw 38 in the above mentioned Patent 2,633,020.

The actuator slide 20 is formed with an opening 23 from its upper to its lower side, said opening being prefervided with upwardly presented skids 25 contacting with the pilot plane 13, said skids being so located as to preclude any tilting of the carrier block 24 with respect to said pilot plane 13. Three skids, located as shown or in some equivalent manner, will sufiice for this purpose.

Suitable springs 26 are provided to act upwardly on the carrier block 24 and react downwardly 0n the actuator slide 20, thereby holding the skids 25 in firm contact with the pilot plane 13. In the present disclosure, the springs 26 are shown of the leaf type and are secured to Patented Dec. 1, 1959-;

a: plate- 27'which is in turn secured by screws 28, Figure 4, upon the tracer unit carrier block 24.

A tracer 29 is carried by the tracer unit carrier block 24 for contact with the workpiece 30 being tested, and said tracer may be mounted in various conventional ways with one being on the outer end of a vertically tiltable beam 31 extending into a tracer unit casing 32, said casing being secured by screws 33 to the lower side of the tracer unit carrier block 24. Tilting of the beam 31 through movement of tracer 29, when moved in contact with the surface of the workpiece is utilized to operate any desired electrical, magnetic, electronic, piezo-electric, or other indicating means, forming no part of the present invention, to indicate inaccuracies in the profile of the workpiece 30 and to record such inaccuracies if desired.

Endwisemovements imparted to the actuator slide are transmitted to the tracer unit carrier block 24 and the assembly which includes tracer 29. If any original or developed inaccuracies in the guideways 19 should cause any deviations in the movement of the actuator slide; 20 from the intended plane of operation, this slide may move with respect to the carrier block 24 and there-- fore cannot transmit any of its deviating movements to said carrier block 24. and the tracer 29, since the plane of movement of the latter is controlled through skids 25 in contact with pilot plane 13 of pilot block 12.

From the foregoing it will be seen that novel and advantageous construction has been disclosed for attaining the. desired ends of controlling the path of movement of the carrier block 24 which supports casing 32 and tracer 29 carried thereby. However, it is to be understood that variations may well be made within the spirit and scope of the invention as set forth. Directional terms such as vertical, lower, upwardly, downwardly, et cetera, have been used to facilitate description of the assembly as shown in the drawings and are not to be construed as limiting the invention herein set forth since it can be operated in various positions providing the tracer point, under conditions of use, is in contact with and moved substantially parallel with the face of the workpiece being investigated.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the apparatus herein disclosed, provided the means stated by any of the claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a profile inspecting device of the general type having anv indicator-actuating tracer carried by a tracer unit casing, and. a pilot means having a pilot plane mounted in substantially parallel relation with the surface to be tested; a tracer unit carrier on which said tracer unit casing with its tracer is operatively mounted, said carrier of said tracer unit casing being slidably engaged with said pilot plane in a manner to be guided by same and preclude any tilting of said carrier and said tracer unit casing with respect to said pilot plane, an actuator for said carrier, means mounting said actuator for movement in a plane substantially parallel with said pilot plane, and means connecting said actuator and carrier so as to allow limited deviation of said actuator from its intended plane of movement without correspondingly moving. said carrier, said connecting means also including means for holding said carrier in operative contact with said pilot plane.

2. A structure as specified in claim 1, in which said actuator is formed with an opening loosely receiving said carrier so as to facilitate movement of the latter back and forth through said actuator to establish said operative connection while permitting said carrier to be guided by said pilot plane.

3. A structure as specified in claim I, in which said actuator is mounted for sliding movement, said actuator being formed with an opening. loosely receiving; said carrier so as to facilitate movement of the latter back and forth through said actuator to establish said operative connection while permitting said carrier to be guided by said pilot plane.

4. A structure as specified in claim 1, in which spring means are provided to hold said carrier in contact with said pilot plane, said spring means simultaneously acting on said carrier and reacting on said actuator.

5. A structure as specified in claim 1, in which said pilot plane faces said carrier which, in turn, is disposed adjacent and substantially parallel to said pilot plane, and spring means are provided to hold said carrier in- Opera tive relation with said pilot plane while permitting relative movement of said carrier to said actuator, said spring means acting on said carrier and reacting in opposite direction on said actuator.

6. In a profile inspecting device, a support, apilot block mounted fixedly on said support and having a lower surface constituting a pilot plane, a carrier block under said pilot block and having a plurality of skids contact-- ing with said pilot plane, said skids being located to-preclude any tilting of said carrier block with respect to said pilot plane, an indicator-actuating tracer carried by said carrier block, an actuator slide under said pilot block and having an opening loosely receiving said carrier block, said support having guideways mounting said actuator slide for movement in a plane substantially parallel with said pilot plane, and spring means acting upwardly on said carrier block and reacting downwardly on said slide, the aforesaid opening allowing deviation of said actuator slide from its intended plane of movement without imparting corresponding deviating. movements to said carrier block.

7. In a profile inspecting device of the general type having an indicator-actuating tracer, and a pilot plane mounted in substantially parallel relation with the stir-- face to be tested; a tracer unit carrier on which said. tracer is operatively mounted, said carrier being: slidably engaged with said pilot plane in a manner to preclude any tilting of said carrier with respect to said pilot plane", an actuator for said carrier, means mounting. said actuator for movement in a plane substantially parallel with said: pilot plane, said actuator and carrier having an opera-' tive connection constructed and arranged to allow limited devation of said actuator from its intended plane of movement without correspondingly moving said car-- rier, and means holding said carrier in operative contact with said pilot plane, said carrier having a plurality of skids contacting with and slidable on said pilot plane and located to preclude said tilting of said carrier.

References Cited in the file of this patent UNITED STATES PATENTS 

